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