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