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