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