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