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