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