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