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