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