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