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