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