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