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