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