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