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