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