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