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