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