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