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