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