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