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