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