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