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