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