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