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)(11,19)(12,22)(13,17)(14,20)(15,16)(18,24)(21,23)(25,26)(27,36)(28,39)(29,33)(30,35)(31,34)(32,37)(38,40) involution — undirected(1,3,5,4)(2,6,8,7)(9,11)(10,15)(12,20)(13,16)(14,21)(17,19)(18,23)(22,24)(25,27)(26,32)(28,31)(29,37)(30,38)(33,36)(34,40)(35,39)(1,3,5,4)(2,7,8,6)(9,12,14,15,13,23,24,19)(10,16,18,22,17,11,20,21)(25,28,30,37,29,38,31,27)(26,32,34,39,33,36,35,40)(1,4,5,3)(2,7,8,6)(10,17)(11,16)(18,20)(21,22)(26,33)(27,37)(28,38)(34,35)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.