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