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