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