One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,5)(6,8)(9,10,13,15)(11,17,19,14)(12,16,21,23)(18,24,20,22)(25,26,30,33)(27,34,29,31)(28,32,36,39)(35,40,37,38)(2,5)(6,7)(9,11,13,19)(10,14,15,17)(12,18,21,20)(16,22,23,24)(25,27,30,29)(26,31,33,34)(28,35,36,37)(32,38,39,40)(1,2)(3,6)(4,5)(7,8)(10,15)(14,17)(16,23)(22,24)(28,36)(32,39)(35,37)(38,40) involution — undirected(1,3)(2,6)(4,8)(5,7)(9,11)(10,14)(12,20)(13,19)(15,17)(16,24)(18,21)(22,23)(25,26)(27,31)(28,32)(29,34)(30,33)(35,38)(36,39)(37,40) involution — undirected(9,10)(11,14)(12,16)(13,15)(17,19)(18,22)(20,24)(21,23)(25,28)(26,32)(27,35)(29,37)(30,36)(31,38)(33,39)(34,40) involution — undirected(9,12)(10,16)(11,18)(13,21)(14,22)(15,23)(17,24)(19,20)(25,29,30,27)(26,31,33,34)(28,37,36,35)(32,38,39,40)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.