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