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