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