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