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