One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,5,7,8)(9,10)(11,15)(12,16)(13,19)(14,17)(18,21)(20,23)(22,24)(25,26)(27,35)(28,38)(29,34)(30,31)(32,37)(33,39)(36,40)(9,11,14,19)(10,15,17,13)(12,18,22,20)(16,21,24,23)(25,27)(26,32)(28,36)(29,39)(30,35)(31,37)(33,40)(34,38)(1,2)(3,5)(4,6)(7,8)(9,11)(10,13)(12,18)(14,19)(15,17)(16,23)(20,22)(21,24)(25,28,31,39)(26,33,30,38)(27,36,37,29)(32,40,35,34)(3,7)(5,8)(9,11)(10,13)(12,20)(14,19)(15,17)(16,21)(18,22)(23,24)(25,29)(26,34)(27,28)(30,40)(31,36)(32,33)(35,38)(37,39) involution — undirected(1,3)(2,5)(4,7)(6,8)(9,12)(10,16)(11,18)(13,23)(14,22)(15,21)(17,24)(19,20)(25,27)(26,35)(28,36)(29,39)(30,32)(31,37)(33,34)(38,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,13)(10,11)(12,21)(14,15)(16,20)(17,19)(18,24)(22,23)(25,30,31,26)(27,35,37,32)(28,38,39,33)(29,40,36,34)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.