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