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